The present invention relates to household appliances and, more particularly, to an apparatus for sharpening blades such as knife-blades and the like.
Various types of sharpening devices are known in the art for sharpening blades for knives such as common household kitchen knives, hunting knives, fishermens"" knives, etc., and blades disposed on ice skates, etc. Many of these known sharpening devices have only one sharpening surface, which limits the quality or type of sharpening that they provide. Usually, different types of sharpening are desirable depending on the particular blade. Using a common household kitchen as an example, knife-blades for tough tasks such as butchery, typically have stronger blades that require a higher degree or level of sharpening to perform these tasks. On the other hand, knife-blades for lighter tasks, such as slicing bread, do not have as strong blades and require a comparatively lower degree or level of sharpening. Other knife-blades, such as those for cutting vegetables and fruit, etc., may need more than one, or a combination of different levels or degrees of sharpening. Such varying types of sharpening needs are not satisfied by knife sharpeners that offer only one type of sharpening surface since a single sharpening surface produces only a single type of sharpened blade. Having a plurality of sharpening surfaces would help facilitate the sharpening of different types of blades, because a plurality of sharpening surfaces can offer a plurality of levels or degrees of sharpened blades.
Some known devices have a plurality of separate sharpening surfaces to offer different levels or degrees of sharpening. These devices, however, usually have drawbacks. For example, the sharpening devices disclosed in U.S. Pat. Nos. 6,267,652, 6,113,476 and 5,611,726 each have a plurality of sharpening surfaces. However, during operation, when a blade is inserted into the sharpening device and against a sharpening surface, such as a wheel having an abrasive surface thereon, the sharpening surface or wheel moves with respect to the blade being sharpened. This is because the force of the blade against the wheel causes the wheel to move away from the blade along the drive-shaft which drives the wheel of the sharpening device. Such movement of the wheel away from the blade causes the force of the sharpening surface of the wheel against the blade to be, at the maximum, the same as the force of the yieldable sharpening surface against the blade.
Further, if additional force is desired between the blade and the sharpening surface of the wheel to achieve more sharpening, such as when the abrasiveness of the sharpening surface has worn with use, the user cannot achieve better sharpening of the blade, at least not with this type of sharpening device. This is because the user cannot apply additional force upon the blade or on the wheel with the abrasive surface to achieve more sharpening of the blade, because the wheel with the abrasive surface simply yields to additional force and moves along the drive shaft. Thus, as stated above, the force of the sharpening surface of the wheel against the blade is, at the most, equal to the force of the yieldable wheel against the blade.
Accordingly, there is a need for an improved sharpening device that offers a plurality of levels or degrees of sharpening, wherein the user may control the sharpening achieved from the sharpening surface of a sharpening device.
An object of the present invention is to provide a blade sharpening apparatus which has a plurality of levels or degrees of sharpening and which provides control of the sharpening of the blades inserted therein.
Specifically, the sharpening apparatus includes a housing, a rotatable drive shaft disposed in the housing, a driving means associated with the drive shaft to rotate the drive shaft, and a plurality of sharpening wheels substantially fixedly attached to the drive shaft. Each sharpening wheel has a sharpening surface thereon. The abrasiveness of the sharpening surfaces on the sharpening wheels can vary between sharpening surfaces to offer different degrees or levels of sharpening. A sliding block associated with each of the plurality of sharpening surfaces is slidable with respect to the drive shaft. The housing includes a slot corresponding to each of the plurality of sharpening surfaces, with each slot disposed angularly in the housing with respect to the respective sharpening surface.
During operation the sharpening wheels rotate with the drive shaft. A user can insert a blade into a slot corresponding to a sharpening surface on a sharpening wheel with the degree or level of sharpening desired. A sliding block associated with the respective sharpening surface is slidable with respect to the drive shaft. The sliding block slidingly yields when the blade is inserted into the slot for sharpening. The sliding block applies force on the blade towards the sharpening surface to sharpen the blade. The user can adjust the force on the blade against the sharpening surface on the sharpening wheel to increase or decrease the sharpening effect of the sharpening surface upon the blade.
In one embodiment, the apparatus includes a removable magnet underneath the sharpening wheels to attract and trap metal filings and metallic dust, etc., discharged during sharpening operations. The user can selectively remove the removable magnet and appropriately discard the trapped material.
There has thus been outlined, rather broadly, some features consistent with the present invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features consistent with the present invention that will be described below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment consistent with the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. Methods and apparatuses consistent with the present invention are capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract included below, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the methods and apparatuses consistent with the present invention.